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List<T>.RemoveRange(Int32, Int32) Method

Definition

Namespace:
System.Collections.Generic
Assemblies:
mscorlib.dll, System.Collections.dll
Assemblies:
netstandard.dll, System.Collections.dll
Assembly:
System.Collections.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll
Source:
List.cs
Source:
List.cs
Source:
List.cs
Source:
List.cs

Removes a range of elements from the List<T>.

public:
 void RemoveRange(int index, int count);
public void RemoveRange(int index, int count);
member this.RemoveRange : int * int -> unit
Public Sub RemoveRange (index As Integer, count As Integer)

Parameters

index
Int32

The zero-based starting index of the range of elements to remove.

count
Int32

The number of elements to remove.

Exceptions

ArgumentOutOfRangeException

index is less than 0.

-or-

count is less than 0.

ArgumentException

index and count do not denote a valid range of elements in the List<T>.

Examples

The following example demonstrates the RemoveRange method and various other methods of the List<T> class that act on ranges. After the list has been created and modified, the RemoveRange method is used to remove two elements from the list, beginning at index ___location 2.

using System;
using System.Collections.Generic;

string[] input = { "Apple",
                   "Banana",
                   "Orange" };

List<string> fruits = new List<string>(input);

Console.WriteLine("\nCapacity: {0}", fruits.Capacity);
Console.WriteLine();

foreach (string fruit in fruits)
{
    Console.WriteLine(fruit);
}

Console.WriteLine("\nAddRange(fruits)");
fruits.AddRange(fruits);

Console.WriteLine();
foreach (string fruit in fruits)
{
    Console.WriteLine(fruit);
}

Console.WriteLine("\nRemoveRange(2, 2)");
fruits.RemoveRange(2, 2);

Console.WriteLine();
foreach (string fruit in fruits)
{
    Console.WriteLine(fruit);
}

input = new string[] { "Mango",
                       "Pineapple",
                       "Watermelon" };

Console.WriteLine("\nInsertRange(3, input)");
fruits.InsertRange(3, input);

Console.WriteLine();
foreach (string fruit in fruits)
{
    Console.WriteLine(fruit);
}

Console.WriteLine("\noutput = fruits.GetRange(2, 3).ToArray()");
string[] output = fruits.GetRange(2, 3).ToArray();

Console.WriteLine();
foreach (string fruit in output)
{
    Console.WriteLine(fruit);
}

/*
    This code example produces the following output:

    Capacity: 3

    Apple
    Banana
    Orange

    AddRange(fruits)

    Apple
    Banana
    Orange
    Apple
    Banana
    Orange

    RemoveRange(2, 2)

    Apple
    Banana
    Banana
    Orange

    InsertRange(3, input)

    Apple
    Banana
    Banana
    Mango
    Pineapple
    Watermelon
    Orange

    output = fruits.GetRange(2, 3).ToArray()

    Banana
    Mango
    Pineapple
*/

Imports System.Collections.Generic

Partial Public Class Program
    Public Shared Sub ShowFruits()

        Dim input() As String = { "Apple", _
                                  "Banana", _
                                  "Orange" }

        Dim fruits As New List(Of String)(input)

        Console.WriteLine(vbLf & "Capacity: {0}", fruits.Capacity)
        Console.WriteLine()

        For Each fruit As String In fruits
            Console.WriteLine(fruit)
        Next

        Console.WriteLine(vbLf & "AddRange(fruits)")
        fruits.AddRange(fruits)

        Console.WriteLine()
        For Each fruit As String In fruits
            Console.WriteLine(fruit)
        Next

        Console.WriteLine(vbLf & "RemoveRange(2, 2)")
        fruits.RemoveRange(2, 2)

        Console.WriteLine()
        For Each fruit As String In fruits
            Console.WriteLine(fruit)
        Next

        input = New String() { "Mango", _
                               "Pineapple", _
                               "Watermelon" }

        Console.WriteLine(vbLf & "InsertRange(3, input)")
        fruits.InsertRange(3, input)

        Console.WriteLine()
        For Each fruit As String In fruits
            Console.WriteLine(fruit)
        Next

        Console.WriteLine(vbLf & "output = fruits.GetRange(2, 3).ToArray")
        Dim output() As String = fruits.GetRange(2, 3).ToArray()

        Console.WriteLine()
        For Each fruit As String In output
            Console.WriteLine(fruit)
        Next

    End Sub
End Class

' This code example produces the following output:
'
' Capacity: 3
'
' Apple
' Banana
' Orange
'
' AddRange(fruits)
'
' Apple
' Banana
' Orange
' Apple
' Banana
' Orange
'
' RemoveRange(2, 2)
'
' Apple
' Banana
' Banana
' Orange
'
' InsertRange(3, input)
'
' Apple
' Banana
' Banana
' Mango
' Pineapple
' Watermelon
' Orange
'
' output = fruits.GetRange(2, 3).ToArray
'
' Banana
' Mango
' Pineapple

Remarks

The items are removed and all the elements following them in the List<T> have their indexes reduced by count.

This method is an O(n) operation, where n is Count.

Applies to

See also